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ABSTRACT:
PROVIDER: PRJNA682394 | ENA |
REPOSITORIES: ENA
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Project description:The genomic DNAs of strains 263 of L. infantum and five derived independent resistant mutants to 5-fluorouracil were used in comparative genomic hybridizations to reveal the deletion and/or amplification events occured by drug resistance mechanisms. The human protozoan parasites Leishmania are prototrophic for pyrimidines and de novo pyrimidine biosynthesis is necessary for their growth. Five independent L. infantum mutants were selected for resistance to the pyrimidine analogue 5-fluorouracil (5-FU) in the hope to better understand the metabolism of pyrimidine in Leishmania. Analysis of the 5-FU mutants by comparative genomic hybridization and whole genome sequencing revealed amplification and deletion events as well as point mutations in metabolic genes involved in either the uridine salvage, folate or dTMP biosynthesis pathways. In particular, a dhfr-ts containing amplicon was observed in two mutants and a deletion of part of chromosome 10 was detected in one mutant. Point mutations in uridine phosphorybosyl transferase (UPRT), thymidine kinase (TK) and uridine phosphorylase (UP) were also discovered. Transfection experiments confirmed that these molecular alterations were responsible for the 5-FU resistance phenotype. Transport studies revealed that one resistant mutant was defective for uracil and 5-FU import although the identity of the transporter remains elusive. This study provided further insights in pyrimidine metabolism in Leishmania and confirmed that multiple mutations can co-exist in a cell to lead to resistance. Each independent resistant mutant to 5-fluorouracil was hybridizated with the wild-type L. infantum 263 to 10 microarrays, each with three biological replicates (independent cultures).
2013-12-31 | E-GEOD-45866 | biostudies-arrayexpress
Project description:The genomic DNAs of strains 263 of L. infantum and five derived independent resistant mutants to 5-fluorouracil were used in comparative genomic hybridizations to reveal the deletion and/or amplification events occured by drug resistance mechanisms. The human protozoan parasites Leishmania are prototrophic for pyrimidines and de novo pyrimidine biosynthesis is necessary for their growth. Five independent L. infantum mutants were selected for resistance to the pyrimidine analogue 5-fluorouracil (5-FU) in the hope to better understand the metabolism of pyrimidine in Leishmania. Analysis of the 5-FU mutants by comparative genomic hybridization and whole genome sequencing revealed amplification and deletion events as well as point mutations in metabolic genes involved in either the uridine salvage, folate or dTMP biosynthesis pathways. In particular, a dhfr-ts containing amplicon was observed in two mutants and a deletion of part of chromosome 10 was detected in one mutant. Point mutations in uridine phosphorybosyl transferase (UPRT), thymidine kinase (TK) and uridine phosphorylase (UP) were also discovered. Transfection experiments confirmed that these molecular alterations were responsible for the 5-FU resistance phenotype. Transport studies revealed that one resistant mutant was defective for uracil and 5-FU import although the identity of the transporter remains elusive. This study provided further insights in pyrimidine metabolism in Leishmania and confirmed that multiple mutations can co-exist in a cell to lead to resistance.
2013-12-31 | GSE45866 | GEO
Project description:Fluoropyrimidines are the backbone of chemotherapy regimes used to treat metastatic colorectal cancer (CRC). These drugs act in different pathways of folate metabolism altering DNA synthesis mainly by inhibition of the tymidylate synthase. For this reaction the 5,10-methylenetetrahydrofolate acts as cofactor. It has been demonstrated that A1298C and C677T polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene result in reduced enzyme activity that leads to reduced availability of this important cofactor. Hence, we hypothesized that the presence of these polymorphisms are related to the efficacy and toxicity of fluoropyrimidines in patients with CRC.
| 2298058 | ecrin-mdr-crc
Project description:The uploaded model is linked to the Scientific Reports article: Subramanian, A., Sarkar, R.R. Revealing the mystery of metabolic adaptations using a genome scale model of Leishmania infantum . Sci Rep 7, 10262 (2017). https://doi.org/10.1038/s41598-017-10743-x. Human macrophage phagolysosome and sandfly midgut provide antagonistic ecological niches for Leishmania parasites to survive and proliferate. Parasites optimize their metabolism to utilize the available inadequate resources by adapting to those environments. No genome-scale metabolic reconstruction was available for Leishmania infantum previously. Hence, we proposed a reconstructed genome-scale metabolic model for Leishmania infantum JPCM5, the analyses of which not only captures observations reported by metabolomics studies in other Leishmania species but also divulges novel features of the L. infantum metabolome. This manually reconstructed genome-scale metabolic network model (iAS556) contains 1260 reactions and 1160 metabolites. Our results indicate that Leishmania metabolism is organized in such a way that the parasite can select appropriate alternatives to compensate for limited external substrates. A dynamic non-essential amino acid motif exists within the network that promotes a restricted redistribution of resources to yield required essential metabolites. Further, subcellular compartments regulate this metabolic re-routing by reinforcing the physiological coupling of specific reactions. This unique metabolic organization is robust against accidental errors and provides a wide array of choices for the parasite to achieve optimal survival.
2020-10-13 | MODEL2010130001 | BioModels
Project description:Transcriptional analyses of L. infantum promastigote compared to L. infantum intracellular amastigote, and L. major promastigote compared to L. major intracellular amastigote The full-genome DNA microarray includes one 70mer-oligonucleotide probe for each gene of L. infantum and for each gene of L.major LV39 Keywords: stage-specific comparison Leishmania infantum: Two-condition experiment, promastigote stage vs amastigote stage. Six biological replicates for each stage, independently grown and harvested. One replicate per array Leishmania major: Two-condition experiment, promastigote stage vs amastigote stage. Four biological replicates for each stage, independently grown and harvested. One replicate per array
2008-05-28 | E-GEOD-10407 | biostudies-arrayexpress
Project description:To investigate dendritic cells-Leishmania interaction, the transcriptional profile of bone marrow-derived dendritic cells (BMDCs) infected with Leishmania infantum or of cells exposed to chemically inactivated parasites was assessed
2022-08-03 | GSE204807 | GEO
Project description:Study hypothesis: Increasing folate status and the MethyleneTetraHydroFolate Reductase (MTHFR) C677T genotype influence intermediary biomarkers of preclinical neoplasia (DeoxyriboNucleic Acid [DNA] methylation and uracil misincorporation) in human colonic epithelium.
Primary outcome(s): Changes in genomic and gene specific DNA methylation and uracil misincorporation.
| 2417579 | ecrin-mdr-crc
Project description:This is an SBML version of the folate cycle model model from:
A mathematical model of the folate cycle: new insights into folate homeostasis.
Nijhout HF, Reed MC, Budu P, Ulrich CM
J. Biol. Chem.,2004, 279
(53),55008-16
Reference publication: 15496403
Abstract:
A mathematical model is developed for the folate cycle based on standard biochemical kinetics. We use the model to provide new insights into several different mechanisms of folate homeostasis. The model reproduces the known pool sizes of folate substrates and the fluxes through each of the loops of the folate cycle and has the qualitative behavior observed in a variety of experimental studies. Vitamin B(12) deficiency, modeled as a reduction in the V(max) of the methionine synthase reaction, results in a secondary folate deficiency via the accumulation of folate as 5-methyltetrahydrofolate (the "methyl trap"). One form of homeostasis is revealed by the fact that a 100-fold up-regulation of thymidylate synthase and dihydrofolate reductase (known to occur at the G(1)/S transition) dramatically increases pyrimidine production without affecting the other reactions of the folate cycle. The model also predicts that an almost total inhibition of dihydrofolate reductase is required to significantly inhibit the thymidylate synthase reaction, consistent with experimental and clinical studies on the effects of methotrexate. Sensitivity to variation in enzymatic parameters tends to be local in the cycle and inversely proportional to the number of reactions that interconvert two folate substrates. Another form of homeostasis is a consequence of the nonenzymatic binding of folate substrates to folate enzymes. Without folate binding, the velocities of the reactions decrease approximately linearly as total folate is decreased. In the presence of folate binding and allosteric inhibition, the velocities show a remarkable constancy as total folate is decreased.
A curated
version of this model is available: BIOMD0000000213
.
This model originates from BioModels Database: A Database of Annotated Published Models (http://www.ebi.ac.uk/biomodels/). It is copyright (c) 2005-2012 The BioModels.net Team.
For more information see the terms of use
.
To cite BioModels Database, please use: Li C, Donizelli M, Rodriguez N, Dharuri H, Endler L, Chelliah V, Li L, He E, Henry A, Stefan MI, Snoep JL, Hucka M, Le Novère N, Laibe C (2010) BioModels Database: An enhanced, curated and annotated resource for published quantitative kinetic models. BMC Syst Biol., 4:92.
2005-01-01 | MODEL6655501972 | BioModels
Project description:This SuperSeries is composed of the following subset Series: GSE9947: Transcriptional analysis of Leishmania infantum methotrexate resistant strains using full-genome DNA microarrays GSE9948: Transcriptional analysis of Leishmania major methotrexate resistant strains using full-genome DNA microarrays Keywords: SuperSeries Refer to individual Series
2010-05-25 | E-GEOD-9949 | biostudies-arrayexpress
Project description:Gene expression profiling to address the effects of infection with Leishmania infantum during distinct clinical outcomes as active visceral leishmaniasis (VL), remission of disease and asymptomatic infection.
2016-10-25 | GSE77528 | GEO